1. Field of the Invention
This invention relates to the field of adjustable pipe wrenches and, more particularly, to self-adjusting pipe wrenches.
2. Prior Art
Pipe wrenches are well-known in the art. A typical prior art wrench has a rotatable screw member which causes the jaw to be selectively moved upward or downward by rotation of such member. When it is desired to use such a wrench, the wrench is opened until the user believes that the jaws will fit about the desired object. The jaws are then placed about the object and fine adjustment is made with the rotatable member such that the jaws of the wrench securely positions the article therein. While these types of wrenches are effective with respect to positioning an article between the jaws, it is necessary to rotate the adjusting member until the exact positioning of the jaws is achieved. This is time consuming and presents a problem, especially in a area which is constrained as to space.
The prior art also teaches adjustable pipe wrenches without the conventional screw member mechanism. For example, Bonner, U.S. Pat. No. 737,199, discloses a sliding adjustable wrench in which the movable jaw is provided with teeth which engage corresponding teeth on the wrench handle and is urged into engagement by a spring.
Another prior art wrench is disclosed by Werner, U.S. Pat. No. 1,784,123. Werner teaches disengagement of the adjustable wrench by pressure on a yoke which disengages teeth located on both the handle and the movable jaw member.
Yet a further prior art wrench is disclosed by Bartenstein, U.S. Pat. No. 1,168,844. Bartenstein discloses an adjustable wrench in which pressure on the movable jaws causes disengagement of one section of the wrench with respect to another.
While these prior art disclosures provide simple means of adjustment of a pipe wrench by way of a rotatable screw member the present invention employs a uniquely designed locking member and automatic, self-adjusting return mechanism which are interrelated, whereby when the locking member is disposed from a first position into a second position, the slidably mounted jaw member is urged forceably down to close about the desired article. This movement is not accomplished by rotation or other movement of any other member as required by the prior art, but is provided for in an automatic manner by a uniquely designed return mechanism which couples a moveable jaw to the wrench handle. Thus, while the prior art wrenches do provide for adjustable jaw members, such adjustment is not by means of a self-adjusting automatic return mechanism and an associated locking member.